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Danger! Mercury rising!

In Brazilian Amazonia, farmers have been slashing and burning the tropical rainforest for many years, as a way of clearing it and improving the fertility of the naturally poor and acidic soil. But this practice also makes the soil vulnerable to erosion by rain.

Image: burning for clearing
burning for clearing

Image: researcher: Robert Davidson
researcher: Robert Davidson

In the Rio Tapajos region, a UQÀM research team, with members from the Montréal Biodôme and Brazilian universities, has shown that growing crops on this burned land causes naturally occurring mercury to leach into nearby waterways.

Image: eruption

Mercury is an element that spews out of volcanoes, travels long distances and settles over widespread areas. It occurs abundantly in this part of the world and has accumulated over more than a million years.

Image: river

In waterways, this “metallic” mercury is transformed into “organic” methyl mercury, which then accumulates all the way up the food chain.

Video: river fishing

Since fish is the main source of protein for local residents, they are gradually contaminated by this constant exposure, and their health suffers.

Image: contaminated fish
contaminated fish

Steps have been taken to reduce their exposure, for instance by making changes in their diet. They are being encouraged to eat more herbivorous animals, which are less contaminated.

In the longer term, research studies and work with local residents will focus on sustainable development initiatives, for instance by conserving more trees so as to reduce soil erosion.

Image: Amazonian village
Amazonian village

For more information:
Life inside epiphytes | Biological pest control | Danger! Mercury rising! | Descriptive records

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